Multiple resolution, multi-stream video system using a single standard decoder

Abstract

A video system is disclosed in which a single generic MPEG standard encoder (107) is used to simultaneously code and compress plural different resolution video signals from a single input video signal; and in which a single generic MPEG standard decoder (402) is used to simultaneously decode plural coded and compressed video signals of different resolutions and form a single composite video signal. The coder converts each frame of pixel data of the input video signal into plural frames having different resolutions, which are then combined into a common frame (106) for input to the generic MPEG encoder. The MPEG encoder produces a single coded and compressed output bitstream in slices of macroblocks of pixel data, which output bitstream is demultiplexed (108) into separate resolution bitstreams using Slice Start Code identifiers associated with each slice and Macroblock Address Increments associated with the first macroblock in each slice, to properly route each slice to the appropriate output. The decoder processes (405) the slices within the coded and compressed bitstreams of different resolutions received from plural sources using the Slice Start Codes and Macroblock Address Increments of each slice to produce a single composite bitstream of successive slices. By merging the slices from the plural sources into the composite bitstream in a predetermined manner, the generic MPEG decoder produces a digital output video signal that is a composite of the different resolution input video signals.

The invention claimed is: 
     
       1. A video decoding system for simultaneously decoding plural input bitstreams representing coded and compressed pixel data from frames of associated plural input video signals of plural input images to form a single output bitstream representing decoded and decompressed pixel data in frames of an output video signal that is a composite of the frames of the plural input video signals, each of said coded and compressed input bitstreams being coded and compressed in a frame divisible format of successive slices which represent the coded and compressed pixel data in one or more macroblocks of pixels in a frame of the associated input video signal, each slice having an identifiable delineated slice start code (SSC) which identifies a row of the slice in the frame of the associated input video signal, and a first macroblock in each slice having an identifiable macroblock address increment (MAI) which identifies the position of that first macroblock in the slice relative to a fixed position in the frame and which can be retrieved from the coded and compressed pixel data in the slice in the input bitstream, the system comprising: a plurality of storage means, each storage means for storing a portion of one of said input bitstreams that represents the coded and compressed pixel data in a frame of the associated input video signal;   processing means for multiplexing slices of the coded and compressed pixel data from the stored portions of the input bitstreams in said plurality of storage means in a predetermined manner to form a combined bitstream of successive slices of coded and compressed pixel data that represents coded and compressed pixel data in a composite frame that is a composite of the frames of the input video signals associated with the multiplexed input bitstreams, the SSC of each slice being renumbered as necessary in the combined bitstream according to the row of the pixel data associated with the slice in the composite frame and the MAI of each slice being renumbered as necessary according to the relative position of the first macroblock of the slice in the composite frame; and   a single standard decoder which converts the combined bitstream of successive slices of coded and compressed pixel data associated with the composite frame to a decoded and decompressed composite frame of pixel data, wherein the decoded and decompressed composite frame of pixel data can be decoded and displayed as a single image comprising plural input images associated with the input bitstreams multiplexed by said processing means.   
     
     
       2. The decoding system of claim 1 wherein said single standard decoder is an MPEG standard decoder. 
     
     
       3. The decoding system of claim 1 further comprising a pixel compositor for rearranging the plural images in the composite frame. 
     
     
       4. The decoding system of claim 1 wherein the plural input video signals have different resolutions. 
     
     
       5. The decoding system of claim 4 wherein the different resolutions of the plural input video signals are 1/4, 1/8 and 1/64 of the resolution of the composite frame. 
     
     
       6. A method for simultaneously decoding plural input bitstreams representing coded and compressed pixel data from frames of associated plural input video signals of plural input images to form a single output bitstream representing decoded and decompressed pixel data in frames of an output video signal that is a composite of the frames of the plural input video signals, each of said coded and compressed input bitstreams being coded and compressed in a frame divisible format of successive slices which represent the coded and compressed pixel data in one or more macroblocks of pixels in a frame of the associated input video signal, each slice having an identifiable delineated slice start code (SSC) which identifies a row of the slice in the frame of the associated input video signal, and a first macroblock in each slice having an identifiable macroblock address increment (MAI) which identifies the position of that first macroblock in the slice relative to a fixed position in the frame and which can be retrieved from the coded and compressed pixel data in the slice in the input bitstream, the system comprising: storing a portion of each of the input bitstreams that represents the coded and compressed pixel data in a frame of the associated input video signal;   multiplexing slices of the coded and compressed pixel data from the stored portions of the input bitstreams in a predetermined manner to form a combined bitstream of successive slices of coded and compressed pixel data that represents coded and compressed pixel data in a composite frame that is a composite of the frames of the input video signals associated with the multiplexed input bitstreams, the SSC of each slice being renumbered as necessary in the combined bitstream according to the row of the pixel data associated with the slice in the composite frame and the MAI of each slice being renumbered as necessary according to the relative position of the first macroblock of the slice in the composite frame; and   converting the combined bitstream of successive slices of coded and compressed pixel data associated with the composite frame to a decoded and decompressed composite frame of pixel data using a single standard decoder, wherein the decoded and decompressed composite frame of pixel data can be decoded and displayed as a single image comprising plural input images associated with the multiplexed input bitstreams.   
     
     
       7. The method of claim 6 wherein the single standard decoder is an MPEG standard decoder. 
     
     
       8. The method of claim 6 further comprising the step of rearranging the plural images in the composite frame. 
     
     
       9. The method of claim 6 wherein the plural input video signals have different resolutions. 
     
     
       10. The method of claim 9 wherein the different resolutions of the plural input video signals are 1/4, 1/8 and 1/64 of the resolution of the composite frame. 
     
     
       11. A decoding system for simultaneously decoding plural input bitstreams representing coded and compressed pixel data from frames of associated input image signals to form a single output bitstream representing decoded and decompressed pixel data in a frame of an output image signal that is a composite of the frames of the plural input image signals, each of said coded and compressed input bitstreams being coded in successive segments in which each successive segment is identifiably associated with a predetermined part of the associated input image without fully decoding the input bitstream, the system comprising: means for multiplexing segments from each of the plural input bitstreams in a coded and compressed domain in a predetermined manner to form a combined bitstream of successive segments of coded and compressed pixel data, the segments being ordered in the combined bitstream in such a manner that the combined bitstream represents a coded and compressed single frame that is a composite of the frames of the plural input image signals; and   means for decompressing and decoding the successive segments of the combined bitstream to form a frame of pixel data of an image signal that is a composite of the frames of the plural input image signals.   
     
     
       12. The decoding system of claim 11 further comprising a pixel compositor for rearranging the images within the composite output image. 
     
     
       13. The decoding system of claim 11 wherein the input image signals are video signals. 
     
     
       14. The decoding system of claim 13 wherein the means for decompressing and decoding is an MPEG standard decoder. 
     
     
       15. The decoding system of claim 11 wherein the input image signals have different resolutions. 
     
     
       16. The decoding system of claim 15 wherein the different resolutions of the input image signals are 1/4, 1/8 and 1/64 of the resolution of the composite output image. 
     
     
       17. A method for simultaneously decoding plural input bitstreams representing coded and compressed pixel data from frames of associated input image signals to form a single output bitstream representing decoded and decompressed pixel data in a frame of an output image signal that is a composite of the frames of the plural input image signals, each of said coded and compressed input bitstreams being coded in successive segments in which each successive segment is identifiably associated with a predetermined part of the associated input image without fully decoding the input bitstream, the method comprising the steps of: multiplexing segments from each of the plural input bitstreams in a coded and compressed domain in a predetermined manner to form a combined bitstream of successive segments of coded and compressed pixel data, the segments being ordered in the combined bitstream in such a manner that the combined bitstream represents a coded and compressed single frame that is a composite of the frames of the plural input image signals; and   decompressing and decoding the successive segments of the combined bitstream to form a frame of pixel data of an image signal that is a composite of the frames of the plural input image signals.   
     
     
       18. The method of claim 17 further comprising the step of rearranging the images within the composite output image. 
     
     
       19. The method of claim 17 wherein the input image signals are video signals. 
     
     
       20. The method of claim 18 wherein the step of decompressing and decoding uses an MPEG standard decoder. 
     
     
       21. The method of claim 17 wherein the input image signals have different resolutions. 
     
     
       22. The method of claim 21 wherein the different resolutions of the input image signals are 1/4, 1/8 and 1/64 of the resolution of the composite output image.